Method for coating tubing



May 18; 1943 w. BROWN I METHOD FOR COATING TUBING Filed Jan. 21, 1941 2 Sheets-Sheet 1 I/Kr/ INVENTOR. WALTER BROWN i 3112- F 2 5 ATTORNEYS 2 Shets-Sheet 2 W. BROWN Filed Jan. 21, 1941 METHOD FOR COAT ING TUB I N G May 18, 1943 INVENTOR. WALTER BROWN BY ma ATTORNEYS the Patented May 18, 1943 D STTE Arm"- Application coating metal within the tube to be coated which latter is substantially sealed to maintain the a non-oxidizing atmosphere. After the melting of the coating metal, the tube is transferred to a spinning apparatus which distributes the molten metal to form a uniform coat around the surface of the tube. It has been found, however, that in such process the molten metal will be contnated by its contact with the heated surface of the tube so as to obiectionably change its characteristics.

it is the object of the instant invention to obtain a method in which the coating metal and the tube are serately heated and are only raised to the desired temperature.

21, 1951, Serial N0. 375,346

a mus by welding. E is a. tapering plug formed of graphite or other refractory material which is adapted to close the aperture in the head D. 15 is a small vent aperture, preferably in the plug E, which'will permit the escape of gases from the interior of the tube.

The tube A or a series of tubes of this character are placed within a heating furnace and When properly heated, the plug E is removed, a'funnel is inserted into the aperture in the head D and a suitable quantity of the molten lining metal is introduced through said funnel into the tube. .1 as this step the tube is preferably held in inclined position so that the molten metal will form a, pool in the lower end portion. The funnel is thenremoved, the plug E reinserted to in contact with each other for a brief interval tie the spa operation. It is, however, access to protect the surface of the tube which is to be coated against omolation d the heating process. The invention, therefore, con

in the method and the apparatus as hereinafter set forth.

in the drawings:

Figure l is a longitu 1.. a; s cti through th tube to be coatecl prior to the introduction or the molten metal; I

Y .2 illustrates the method of introducing molten metal into the tube;

Floors 3 is a cross section illustrating a operation Eli e e is a vertical lonsitul section ugh an apparatus for coating the tube both it; and outsioethe e;

the spinclose the aperture after which the tube is trans ferred to a spinning apparatus such as illustrated in Figure 3. This will rapidly rotate the tube so as to uniformly distribute the molten. metal by centrifugal action. After cooling, the heads 18 and D are removed from the tube and may be reused in connection with other tubes. By this method, the molten metal only contacts with the heated tube for a comparatively short time interval and, therefore, does not absorb the metal of the tube to any objectionable extent.

The process as thus far described is per tlcularly applicable for the lining of comparatively long tubes.

7 only line the tube but also to externally coat it,

.1 may employ the apparatus as illustrated in Figures a to 8. Asshown in Figure 4, Q is a cylindrical container of slightly larger diameter than the tube A which is to be coated. H is a Flo ii is a or view thh a slightly modified K30E1?=w 313 M r is is top e i is a p 8 is a section on line to of Figure 7;

it... plan view of Figure 5 with the and e9is

' closure plug removed.

As illustrated in l, A is'a tube which ls'to be lined with another metal. B is a head for clc one end of the tube be pre'fely welded thereto as indicated at C; Dis a cenaped head for closing the Op osite end of the tube which also is pref bly securedhead for closing the lower end of the container G. head has an inner concentric portion of smaller diameter adapted to be inserted in the lower end of the tube A to properly center the same within the container G. The container -G-is of greater height than the tube B anci has inserted in its upper end a head I formed of graphite or refractory material and which,

in cooperation with the head H, centers the tube A. The head I is preferably formed with a central recess J in its upper portion whic is connected by radial channels K with the space between the tube A and container G. The tube- A' is also provided at its upper end with notches L establishing communication between the in terior of the tube and the annular space between the tube and the container. M is upper closure head preferably of; metal which is welded to the container G and serves to hold Where it is desired to notv the head I in position. The head M is centrally apertured to receive a removable closure plug N. with this construction, the container G and its enclosed tube are first heated to the desired temperature after which the plug N is removed and molten coating metal is introduced through the central aperture into the recess J. From here it will flow into the. radial channels K to the space between the tube and container first filling this space and later overflowing through the notches L into the tube where it will form a pool at the lower end. The device is then transferred to the spinning rolls which will'distribute the molten metal within the tube by centrifugal action. v

Figure 5 shows a construction similar to Figur 4 differing'therefrom only in substituting a convex metallic head 0 for the graphite head I.

What I claim as my invention is: 1. The method of coating metallic tubes with a different metal layer of substantial thickness comprising heating the surface to be coated to a high temperature within a substantially closed cylinder containing a non-oxidizing atmosphere, separately melting the coating metal, opening said cylinder and introducing through said opening a quantity of the molten metal, and spinning the cylinder to distribute the molten metal uni-,

- coating metal, opening one end of said cylinder and introducing through said opening a quantity of the molten metal, closing said opening, and spinning said cylinder to distribute the molten metal over said surface and to solidify the samebefore contamination occurs.

3. The method of lining tubes with a different metal layer of substantial thickness comprising closing the opposite ends of a tube to maintain therein a non-oxidizing atmosphere, heating the tube to a high temperature, separately meltinz the coating metal, opening a central port in one of the closed ends of the tube and introducingthrough said port a quantity of the molten metal while said tube is in an inclined position, closing said port, and spinning the tube with its axis horizontal to uniformly distribute the molten metal about the inner surface thereof and to solidify the same before contamination occurs.

4. The method of coating tubes upon both the innerand outer surfaces thereof with a different metal in layers of substantial thickness comprising positioning a tubeconcentrically within a cylindrical container with an annular space between the tube and container, closing the opposite ends of said container to maintain therein a non-oxidizing atmosphere, heating the container and the tube therein to a high temperature, separately melting the coating metal, opening one of the closed ends of the tube and introducing through said opening a quantity of said tube to solidify the molten metal before contamination occurs.

BROWN. 

